My roll n lock is going on 7 years, without any major issues. I have only had one incident where the locking mechanism froze shut during a freezing rain storm, sub zero temps overnight 3 years ago in New York. A quick trip to the car wash fixed it. I would buy another one in a heartbeat.
Great customer service as well. I almost bought a new one when I bought my new truck, but they sold me the short bed rails for $70, so I ended up using the same tonneau from my xrunner.